Reflects the current release of Nintex for SharePoint 2016. For your version, please access assistance through the Help button in the product.
There is a known issue when adding a configuration database.
On the Configuration database page, when the default server name of "LOCALSERVERNAME\Microsoft##SSEE" is used, the following error message is displayed.
An error has occurred while establishing a connection to the server. When connecting to SQL Server, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error:40 - Could not open a connection to SQL server).
The "Microsoft##SSEE" portion of the default server name indicates an embedded instance, which is locked down to other applications. This situation occurs when the SharePoint instance was installed as standalone, without connection to any existing installation of SQL Server.
Install an additional database instance and then update configuration pages in Nintex Word to point to the new database instance. The database instance can coexist on the same server as SharePoint. One option is SQL Server Express, which is free and available from www.microsoft.com.